[Xen-changelog] Fix an out-of-bounds memory access in xc_ptrace.c.

[Xen patchbot-3.0-testing <patchbot-3.0-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID b54bba73936d4c0c6a279108da05b4221cdf58a9
# Parent  be5a6188cd9f00d045328b6b045f85992f2fbe10
Fix an out-of-bounds memory access in xc_ptrace.c.

Currently, Xen always copies the entire 512 byte extended
FPU state (fxsave) even if only the "regular" FPU state was
requested.

This breaks since the memory buffer allocated in
linux-xen-low.c:regsets_fetch_inferior_registers() is only large
enough to hold the "plain" FPU registers.

Signed-Off-By: Simon Kagstrom <simon.kagstrom@xxxxxx>
xen-unstable changeset:   9987:8e6835fa7c4bf262a02fe63418eee1ae3fd16516
xen-unstable date:        Fri May 12 15:47:25 2006 +0100
---
 tools/libxc/xc_ptrace.c |    5 +++++
 1 files changed, 5 insertions(+)

diff -r be5a6188cd9f -r b54bba73936d tools/libxc/xc_ptrace.c
--- a/tools/libxc/xc_ptrace.c   Thu May 11 11:34:34 2006 +0100
+++ b/tools/libxc/xc_ptrace.c   Fri May 12 15:49:11 2006 +0100
@@ -510,6 +510,11 @@ xc_ptrace(
         break;
 
     case PTRACE_GETFPREGS:
+        if (!current_isfile && fetch_regs(xc_handle, cpu, NULL)) 
+                goto out_error;
+        memcpy(data, &ctxt[cpu].fpu_ctxt, sizeof (elf_fpregset_t));
+        break;
+
     case PTRACE_GETFPXREGS:
         if (!current_isfile && fetch_regs(xc_handle, cpu, NULL)) 
                 goto out_error;

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